Gestational diabetes and future risk of diabetes.

Background: In this study of women with gestational diabetes we attempted to (a) Determine the magnitude of the long term risk of progression to diabetes and (b) Identify factors that predict the development of diabetes.

Methods: All women diagnosed with gestational diabetes (GDM) at Worcestershire Royal Hospital, UK from 1995 to 2003 were included in this observational cohort study and followed up till 2009. Diabetes was diagnosed if fasting glucose ≥ 7.0 mmol/L, random/two-hour glucose following 75 gram oral glucose test (OGTT) ≥ 11.1 mmol/L or HbA1c ≥ 7.0%.

Results: The risk of developing diabetes was 6.9% at five years and 21.1% at ten years following the initial diagnosis of GDM. Fasting and post-prandial glucose levels in the oral glucose tolerance test during pregnancy were associated with future risk of diabetes. There was no association with age, gestational age at diagnosis of GDM, numbers of previous and subsequent pregnancies.

Conclusion: Risk of progression to diabetes in a UK based cohort of women with GDM is estimated. Women with fasting antenatal glucose ≥ 7.0 mmol/L and/or an antenatal two-hour glucose ≥ 11.1 mmol/L are at higher risk and need close follow up.